RU2707109C1 - Method for isolation of formation water influx at sections of their supply in wells with horizontal termination - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and is intended for isolation of influx of formation water in horizontal sections of oil producing wells. Method involves extraction of downhole equipment from a well, performance of geophysical investigations in a horizontal section of a well shaft, determination of a water influx interval from an aquifer. At that, flap-type double check valve, emergency disconnector, centralizers, two packers of inflatable action are lowered on flexible pipe equipped with connector, between which by means of coupling connections perforated connection pipe, ball discharge into flexible pipes, pumping of water-insulation composition into flexible pipe, ball release to emergency disconnector, creation of hydraulic pressure, disconnection of flexible pipe from equipment and its lifting to surface, leaving the well waiting for hardening of cement, lowering the equipment with the cutter on the flexible pipe, drilling the perforated branch pipe, inflatable packers and the water isolation composition residues with wash-out to the day surface, lowering the downhole equipment; well development and mode output.

EFFECT: technical result consists in improvement of efficiency of water shutoff operations, isolation of influx of formation water in a cased horizontal section of the wellbore.

1 cl, 7 dwg

Description

The invention relates to the oil industry and is intended to isolate the influx of formation water in horizontal sections of oil wells.

A known method of isolation of produced water using a sleeveless long pipe (RF patent No. 2188929, class 7 ЕВВ 33/13, 2002).

The disadvantage of this method is the impossibility of using it in wells with subhorizontal and horizontal endings, since the method does not allow injection of the water-insulating composition into a predetermined interval of the wellbore.

A known method of conducting waterproofing work in wells with horizontal completion, which consists in pumping through tubing into the flooded interval of the horizontal stem of the waterproofing composition, followed by the installation of a metal shutter from corrugated pipes [RF Patent No. 2114990, cl. 6 ЕВВ 43/32, 33 / 13.1996].

The disadvantage of this method is the difficulty of pumping a water-insulating composition strictly into the flooded interval of the horizontal wellbore.

There is a method of isolating produced water in an uncased horizontal section of a producing well, according to which, after lowering the tubing string to the bottom of the horizontal section of the wellbore, the annular space of the uncased horizontal section is filled with cement mortar, a modified polyvinyl acetate reagent, exposure is carried out for 2-3 hours, followed by washing of the well [ RF patent No. 2273722, cl. ЕВВ 33/13, 2004]. According to the method, a thin, dense, waterproof crust is formed opposite to the intervals of the water-producing strata.

The disadvantage of this method is the ability to quickly break through insulated water into a horizontal wellbore along a thin impermeable crust. This is facilitated by the fact that, as a rule, horizontal trunks are drilled along the bedding, and the permeability of the rocks along the bedding is much higher than in the transverse direction. Therefore, produced water can be easily filtered by bedding along a thin impermeable crust and break into the cavity of a horizontal trunk.

There is also known a method of isolation of water-producing strata [RF Patent No. 2152507, 7 ЕВВ 33/13, 33/19 BI No. 19, 2000], including extraction of pumping equipment from the well, lowering the tubing string into the well, injection through them an insulating solution with fastening properties and forcing it into an insulated formation under excessive pressure. At the same time, as a grouting mortar, plasticized cement mortar is used with SEPACOL CE-5381 reagent or waste water treatment plants.

The disadvantages of this method include the following. The method requires for its implementation of large material costs associated with the installation of a cement bridge with its subsequent drilling after waiting for the hardening of cement (OZZ), as well as a large investment of time.

The closest technical solution adopted for the prototype is a method of isolating the influx of water in a horizontal section of the wellbore of a producing well, including removing pumping equipment from the well, lowering the pipe string into the well, injecting a waterproofing solution with hardening properties through them, creating an impermeable screen in the interval of the water-producing formation and subsequent leaching of the waterproofing solution from the well with reverse circulation after the start of setting the waterproofing composition [RF Patent No. 2578095, opu l. 03/20/2016].

The disadvantage of this method is a significant narrowing of the horizontal section of the wellbore after waterproofing due to the leaving of an expandable sleeve with sealing (rubber) rings, as well as a check valve.

The objective of the invention is to increase the efficiency of water-proofing works, isolating the influx of formation water in a cased horizontal section of the wellbore.

The technical result of the invention is to develop an effective method of isolating the influx of formation water in a horizontal cased section of an oil well bore, pumping a water-insulating composition into a predetermined interval of the horizontal well.

The task and technical result is achieved by the fact that the method of selective isolation of formation water inflow in wells with horizontal completion includes extraction of downhole equipment from the well, conducting geophysical surveys in a horizontal section of the wellbore; determination of the interval of inflow of water from the aquifer; descent on a flexible pipe of equipment consisting of a connector, a double casement type non-return valve, an emergency disconnector, centralizers, two inflatable packers, between which a perforated nozzle is attached using coupling joints; dumping the ball into flexible pipes; pumping a waterproofing compound into a flexible pipe; dumping the ball to the emergency disconnector, creating hydraulic pressure; disconnecting the flexible pipe from the equipment and lifting it to the surface; abandonment of the well while waiting for cement to harden; descent on a flexible pipe of equipment with a mill; drilling perforated nozzle, inflatable packers and the remains of the waterproofing composition with washing to the surface; descent of downhole equipment; well development and conclusion to the regime.

The novelty of the invention lies in the use of a flexible pipe equipped with inflatable packers for selective isolation of formation water inflow in a horizontal section of an oil well.

The invention is illustrated by the drawings depicted in FIG. 1-7.

A well (1) with a horizontal end that has opened a producing formation (2) and has been watered due to breakthrough of formation water (3) from an aquifer (4) is stopped. From the well (1), the downhole equipment used for production is removed (Fig. 1).

Geophysical surveys are carried out in the horizontal section of the wellbore (1) and the interval (3) of water inflow from the aquifer (4) (not shown) is determined.

To do this, a geophysical instrument with a stored cable is lowered into a cased horizontal section of the wellbore on a flexible pipe, the phase composition is determined from the horizontal profile of the well with multiphase composition of the produced products, and the length L of the interval (3) of the aquifer (4) of the cased horizontal section of the wellbore is determined (1 ) subject to waterproofing.

The equipment (5) is lowered on a flexible pipe, consisting of a connector, a double casement type check valve, an emergency disconnector, torus centralizers (not shown), two packers (6) and (7) of inflatable action, between which a perforated nozzle is attached using sleeve couplings (8) (and the interval between the packers (6) and (7) should be 1-2 m longer than the waterlogged interval L) (Fig. 2).

Connector, double check valve, emergency disconnector, as well as centralizers, you can use any known designs. As a pipe (8), a segment of a tubing with pre-cut technological holes is used.

Inflatable packers have bodies (9) and (10), in which there are channels in the form of holes (11) and (12) for pumping the process fluid into the internal cavities located between the bodies (11) and (12) and the rubber sealing elements (13 ) and (14). The rubber sealing elements (13) and (14) are attached to the packer bodies (9) and (10) by means of the locking rings (15) and (16) on the threaded connections (Fig. 3).

Inside the packer (6), above the shoulder (17), there is a spring (18), on top of which is a movable sleeve (19). From above, the movable sleeve (19) is supported by the protrusion (20). The movable sleeve (19) has a seat (21) (Fig. 4).

After the equipped flexible pipe is lowered to the required interval for waterproofing, the ball (22) is discharged into the flexible pipes (5), the ball (22) passing through the flexible pipes (5), the packer (6), enters the saddle (21) of the movable sleeve ( 19) packer (7). After that, pumping (23) in the required volume of the waterproofing composition into the flexible pipe (5) is carried out (Fig. 5).

When injecting, the ball (22) located in the saddle (21) under the influence of hydraulic pressure of the cement composition compresses the movable sleeve (19) of the packer (7), the spring (18) is compressed, the channel (12) opens. The waterproofing composition, pumping into the channel (12), stretches the rubber sealing element (14) of the packer (7), thereby ensuring its contact with the wall of the well casing in the horizontal section of the well (1) (Fig. 6).

As a waterproofing composition for work, a composition known by the patent is recommended [RF Patent No. 2613067. Composition for repair and insulation works in wells / Leontiev D.S., Kustyshev A.V., Kleschenko I.I. and others], including microdur R-U, multifunctional modifier PFM-ISO, superplasticizer F-10 and water at a water-cement ratio of 0.5 in the following ratio, wt. %: microdur R-U 48.75-49.05, multifunctional modifier PFM-ISO 1.0-1.2%, superplasticizer F-10 0.9-1.3%, water - the rest.

Further, in the process of pumping, the grouting composition enters the perforation holes of the perforated pipe (8), as well as into the channel (13) of the packer (6). The rubber sealing element (13) of the packer (6) begins to stretch and compact with the wall of the well casing (1). During the injection of the waterproofing composition, the rubber sealing elements (13) and (14) of the packers (6) and (7) are inflated, the composition is pumped through the perforated holes of the perforated pipe (8) into the flooded interval of the formation.

Then, the ball is dropped into the flexible pipes (5) to the emergency disconnector, hydraulic pressure (for example, water) is supplied, the flexible pipe (5) is disconnected from the equipment and rises to the surface (not shown). After this, the well (1) is left waiting for the cement to harden (OZZ).

After the OZZ, equipment with a cutter (23) is lowered into the well (1) on a flexible pipe and work is underway to drill a perforated pipe (8), packers (6) and (7) and the remains of the waterproofing composition (24) with a washout on the day surface (Fig. . 7).

After finishing work, downhole equipment is lowered into the well (1), the well is mastered and put into operation.

The proposed method for selectively isolating the influx of formation water in a cased horizontal section of the trunk of an oil producing well improves the efficiency of waterproofing works and prolongs the anhydrous period of its operation.

1 - well

2 - reservoir

3 - inflow of formation water

4 - aquifer

5 - flexible pipe

6.7 - inflatable packers

8 - perforated pipe

9, 10 - cases of inflatable packers

11, 12 - channels in the form of holes

13, 14 - rubber sealing elements

15, 16 - snap rings

17 - shoulder

18 - spring

19 - movable sleeve

20 - ledge

21 - saddle

22 - ball

23 - pumping composition

Claims (1)

The method of selective isolation of formation water inflow in wells with horizontal completion, including extraction of downhole equipment from the well, conducting geophysical surveys in the horizontal section of the wellbore, determining the interval of water inflow from the aquifer, characterized in that it is run on a flexible pipe equipped with a dual connector casement check valve, emergency disconnector, centralizers, two inflatable packers, between which with coupling a perforated pipe is attached to the connections, the ball is discharged into the flexible pipes, the water-proofing composition is pumped into the flexible pipe, the ball is discharged to the emergency disconnector, the hydraulic pressure is created, the flexible pipe is disconnected from the equipment and raised to the surface, the well is left to wait for cement to solidify, and the descent to flexible pipe equipment with a mill, drilling perforated pipe, inflatable packers and the remains of the waterproofing composition with washing to the surface, lowering the downhole about equipment; well development and conclusion to the regime.

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